Prior commonly owned U.S. Pat. Nos. 4,272,138 and 4,441,767 to Stark disclose file cabinet drawer anti-tip lock devices, which prevent more than one drawer in a vertical stack of drawers from being opened at a given time, whether opening of a second drawer is attempted simultaneously with or subsequent to the opening of a first drawer. The anti-tip mechanism described therein utilizes a segmented, vertically extending lock bar composed of snubber elements arranged in end-to-end abutment along a side of the cabinet housing, and a plurality of horizontally disposed activator rails each carried by a different drawer and arranged upon opening of an associated drawer to move between the ends of a pair of adjacent snubber elements and effect vertical displacement of the snubber elements, whereby activator rails carried by other drawers are blocked from outward movement.
In the constructions disclosed by the above patents, the activator rails are required to be mounted for sliding movement relative to the drawers, as an incident to drawer opening and closing movements, in order to permit the activator rails to function for snubber element displacement purposes throughout the full range of drawer movements.
In a more recent development, employing snubber elements having a slightly different mode of operation, the activator rails comprise front parts non-movably fixed one to each of the drawers and rear parts slidably supported one by each drawer in horizontal alignment with associated front parts.
In these prior constructions, the slidable activator rails or rail parts have been objected to as creating undesired noise during drawer opening and closing movements.